Press for continuously producing chip board, fiber board or the like

ABSTRACT

A press for continuously producing fiber board, chip board or the like comprising an upper and a lower endless link chain each traveling between a pair of guide rollers rotatable in one direction about parallel horizontal axes, each of said chains consisting of rigid link plates each pivotably connected to the adjacent plates, an endless feed belt surrounding each chain and traveling therewith, a plurality of pressure rollers acting upon the link plates of the inner stringers of both chains, and adjustable hydraulic or pneumatic pressure means acting at least upon each pressure roller for the upper chain, each link plate as seen in the direction of its travel having a length equal to at least twice the distance between the axes of two adjacent pressure rollers of the same chain so that each link plate of each inner chain stringer will be acted upon by the pressure of at least two adjacent pressure rollers.

United States Patent 1191 De Mets Mar.5, 1974 [75] Inventor: Albert DeMets, Roeselare, Belgium [73] Assignec: De Mets N.V.

Konstruktienerkhuizen, Klaasterstraat, Kachtem, Belgium [22] Filed: June12, 1972 21] Appl. No.: 261,668

[30] Foreign Application Priority Data July 14, 1971 Germany 2135230[52] US. Cl 425/371, 100/151, 264/109,

[51] Int. Cl. B29c 15/00 [58] Field of Search... 425/335, 338, 371, 115,130; 264/109, 112, 113, 122; 100/151, 153, 116, 118

Caughey 425/371 X Soda et al. 425/317 X Mallett ct al. 425/115 X PrimaryExaminerRobert L. Spicer, Jr. Attorney, Agent, or FirmCraig andAntonelli [57] ABSTRACT A press for continuously producing fiber board,chip board or the like comprising an upper and a lower endless linkchain each traveling between a pair of guide rollers rotatable in onedirection about parallel horizontal axes, each of said chains consistingof rigid link plates each pivotably connected to the adjacent plates, anendless feed belt surrounding each chain and traveling therewith, aplurality of pressure rollers acting upon the link plates of the innerstringers of both chains, and adjustable hydraulic or pneumatic pressuremeans acting at least upon each pressure r01- ler for the upper chain,each link plate as seen in the direction of its travel having a lengthequal to at least twice the distance between the'axes of two adjacentpressure rollers of the same chain so that each link plate of each innerchain stringer will be acted upon by the pressure of at least twoadjacent pressure rollers.

35 Claims, 3 Drawing Figures PRESS EOR CONTINUOUSLY PRODUCHNG CHEFBOARD, FHBER BOARD OR THE LHKIE The present invention relates to acontinuously operating press for continuously producing chip board,fiber board or the like of a mixture of fibrous material such as woodchips, fibers, cellulose or similar materials and suitable binders. Thispress is of the type which comprises an upper and a lower endless belteach of which forms a link chain the individual links of which consistof rigid steel plates which are pivotally connected to each other attheir longitudinal ends. These two chains are movable around and aretightened longitudinally by guide wheels, preferably of a polygonalperipheral shape, which are rotatable in the same direction abouthorizontal parallel axes. The stringers of these chains facing eachother between which the material is to be compressed are movable alongpressure rollers which are rotatably mounted between the upper and lowerstringers of each chain. The pressure rollers on the link plates atleast of the upper chain are acted upon by the controlled but variablepressure of hydraulic or pneumatic cylinder-'and-piston units whichpress these rollers in the direction toward the opposite pressurerollers of the lower chain and the link plates thereof. One or more of.these pressure rollers of both chains are connected to drive means fordriving the chains at the same speed.

Presses of the type as above described have been previously designed soas to act as so-called preliminary presses for merely compressing theloose material to a certain thickness which is thereafter passed to atleast one further press in which the fiber or chip board is furthercompressed to the desired final thickness and heated so as to set andharden the binder of the mate rial.

' Prior to the disclosure of a press as above described another type ofpress, a so-called caterpillar-chain press, has been disclosed forcontinuously producing chip board or the like under pressure or underpressure and heat. in such a press, a layer of wood chips, saw dust orother comminuted fibrous or cellulose material which is mixed with asuitable binder is at first compressed within a short compression stagebetween the link plates of two chains to the desired final thickness ofthe board to be produced and it is then maintained under a uniformpressure so as to prevent any swelling of the material while being setand hardened. Within the compression stage, the link plates of one chainare guided along a curved path which has such a radius of curvature thatthe upper and lower endless metal belts which are disposed between thetwo chains will not be damaged by being bent when passing around theirguide rollers or guide drums or within the compression stage in whichthe adjacent link plates abut at an angle upon each other while pressingupon the endless belts. During the subsequent setting stage, all linkplates of each of the two chains are disposed within a common straightplane and the adjacent plates of each chain are separated from eachother by slots of such a narrow width that the metal feed belt of thematerial while running in a straight direction covers or bridges thisslot and will be concavely bent only to an insignificant ex tent. Duringthe curved section of the travel of the two chains, however, the slotsbetween the adjacent link plates are widened to such an extent that thesteel belts bridging the slots with a concave curvature within thecompression stage will still remain within the elastic limits of themetal and will withstand the pressure which is exerted upon these belts.As compared with the continuously operating presses at first mentionedabove, these so-called caterpillar-chain presses have particularly thedisadvantage. that the endless chains have to be driven solely by thesprocket wheels at the opposite ends of the press on which each chain isguided so as to reverse the direction of travel of its two stringers.Considering the high rate of compression and solidity which are nowadaysrequired of most fiber or chip board or the like, such caterpillar-chainpresses would have to be made of such a great length that very highforces would be required for driving the sprocket wheels and excessivetensions would occur within the chains causing them to break within ashort time.

The presses as first described have the advantage over thesecatepillar-chain presses that they may be made of any desired lengthsince the endless plate-link chains are not merely driven by their guidewheels, but primarily by at least some of the pressure rollers which actupon the inner stringers of the two chains, that is, the stringers whichface each other. If such a press should have a great length, it ismerely necessary to provide means for positively driving a larger numberor all of the pressure rollers. These presses have, however, thedisadvantage that, since each rigid link plate of the two chains isacted upon only by one pressure roller, it has the tendency to tiltrelative to the adjacent link plates. Since the length of the individuallink plates of the two chains is necessarily limited and the diameter ofthe pressure rollers had to be made relatively large in order to be ableto transmit a sufficient pressure upon the link plates, it wasunavoidable that the finished fiber or chip board when thus continuouslyproduced had small transverse projections or recesses at more or lessuniform distances on its upper and lower sides. These projections orrecesses could not be avoided because it occurred very often that a linkplate was acted upon at the same time only by a single pressure roller,and especially if in the travel of the chains the pressure was exertedonly upon one end part of a link plate, the plate would tilt relative tothe intended plane. This tilting also caused an excessive strain uponthe link pins which pivotally connect the adjacent link plates to eachother.

It is an object of the present invention to improve a continuouslyoperating press of the type as first described above so as to eliminatethe possibility that undesirable deformations of the chip or fiber boardor the like might occur during its production and also so as to preventthe individual link plates of the two chains from being bent and anexcessive strain from being exerted upon the entire chains and upon thelink pins or the like which pivotably connect the adjacent link platesof the two chains to each other. An additional object of the inventionis to provide suitable means for preventing the pressure rollers frombeing bent under the pressure which is exerted on their ends byhydraulic or pneumatic units.

For attaining these objects, the invention provides that each link plateof the two chains has a length equal to at least twice the distancebetween the axes of two adjacent pressure rollers acting upon eachchain. Thus, when the press is in operation to produce fiber or chipboard or the like continuously, each link plate of each chain whilepassing through the compression and setthe adjacent link plates. Thisalso permits the individual pressure rollers to be made of aconsiderably smaller diameter, for example, a diameter of one half orless than that which was previously required, the hydraulic or pneumaticforces which have to be exerted upon the individual pressure rollers maybe considerably lower and be more accurately controlled and the linkplates do not have to be as thick, heavy and solid as they had to bewhen each link plate was acted upon only by one pressure roller.Furthermore, due to the larger number of pressure rollers and also thelarger number of these rollers which are positively driven, the endlessfeed belts which travel along with and around the link plate chains andthen directly between the inner stringers of these chains for feedingthe loose fibrous material continuously toward and between thesestringers and for then transmitting the pressure which is exerted by thepressure rollers upon these inner chain stringers and through the latterduring the compression and setting stages upon the opposite sides of thefibrous material will not be subjected to very high stresses and maytherefore consist of relatively thin and flexible belts of steel,plastic, andsuitable fabric, netting, or the like. Furthermore, thewearing plates which were required in some of the known continuouslyoperating presses betwen the pressure rollers and the like plates maynow be omitted entirely.

Since the pressure rollers which act directly upon the inner chainstringers may now be made of relatively small diameters, it is advisableaccording to the invention to brace at least some of these rollersintermediate their ends, and especially those rollers which determinethe final thickness of the fiber or chip board so as to prevent themfrom bending between theirends which are mounted in bearings and also soas to reduce the stresses and the wear to which these bearings aresubjected. These bracing means preferably consist of smaller rollerswhich act upon the main pressure rollers at least centrally of theirlength and, in turn, are acted upon by hydraulic or pneumatic unitssimilar to those which act at least upon the upper pressure rollers.Even if only the bearings of the upper main pressure rollers arevertically slidable and acted upon by such pressure units,'while thebearings of the lower pressure rollers are mounted in fixed positions,the bracing rollers should also be provided for all those lower pressurerollers which are vertically opposite to the upper pressure rollerswhich are supported by such bracing rollers. If only the upper or lowerpressure rollers would thus be supported, the stresses and wear upon thebearings of the opposite unbraced rollers might become excessive. On allthose pressure rollers on which such bracing rollers are required ordesirable, these bracing rollers are preferably provided in pairs atequal distances from the vertically longitudinal plane of the respectivepressure roller so that, as seen in cross secion, this pressure rollerwill have a uniform three-point support by the lines of engagement withthe two bracing rollers and the line of its engagement with therespective link plate of the upper or lower chain.

The features and advantages of the present invention will become furtherapparent from the following detailed description thereof, which is to beread with reference to the accompanying diagrammatic drawings, in whichFIG. 1 shows a side view of the press according to the invention, someouter parts of which are broken away to show the inside of the press;

FlG. 2 shows a cross section which is taken along the line ll ll of HG.1; while FIG. 3 shows a cross section which is taken along the line lllill of FIG. 2.

As illustrated in the drawings, the press according to the inventionessentially consists of two frames 1 and 2 on each of which an endlesslink chain 3 or 4 is mounted which is composed of link plates 19 or 20,respectively, which are of equal length and are pivotably connected bylink pins or hinges to each other. Each of these chains is surrounded byan endless feed belt 7 or 8, respectively, which preferably consists ofthin fexible steel, but may also consist of plastic or a suitable fabricor a screen material. The inner stringers of the chains 3 and 4, thatis, those facing each other, directly engage upon the correspondingparts of the belts 7 and 8 and are adapted to take along and drive thesebelts at the same speed. Chains 3 and 4 and belts 7 and 8 are mounted sothat between the sides of the belts which are directly acted upon by theopposite chain stringers 19 and 20 a slot is formed in which a layer 21of chips, fibers or the like is compressed between the belts 7 and 8 toform a chip or fiber board of a certain but adjustable thickness. Eachof the opposite end parts of belt 7 is movable along guide rollers 7 theaxes of which are disposed substantially within a semicircle, and theright end part of the lower belt 8 is similarly movable along guiderollers 8, while the left end part of the lower belt 8 which also servesfor feeding the layer 21 of fibers or chips to the press is guided by aguide drum or by similar guide rollers which are not shown in thedrawings since for this feeding movement of the lower belt 8 toward andinto the press, they are spaced at a certain distance from the press asshown in FIG. 1. Since the links 19 and 20 of the two chains 3 and 4consist of rigid plates, the guide wheels 13, 14 and 15, 16 for thesechains which are mounted on parallel horizontal shafts 9, 1t) and ll,12, respectively, are made, for example, of a hexagonal shape and eachstraight outer surface of each of these guide wheels l3 to 16 has alength substantially corresponding to the distance between the link pinsor the like which connect each chain link to the adjacent links of thesame chain.

The inner stringers 5 and 6 of the two chains 3 and 4 are pressed towardeach other by pressure rollers 17 and 18 which also drive the two chainsand the belts 7 and 8 thereon and are rotatably mounted in correspondingpositions opposite to each other so as to engage upon the upper side ofthe stringer 5 of the upper chain 3 and the lower side of the stringer 6of the lower chain 4, respectively. While the lower pressure rollers 18may be rotatably mounted in fixed bearings and their axes are disposedwithin a common horizontal plane, the bearings of each of the upperpressure rollers 17 are connected to and preferably mounted on andvertically movable by adjustable hydraulic or pneu' maticcylinder-and-piston units. A certain number of these upper pressurerollers 17 at the inlet side of the machine, for example, the rollers17a to 1711, form a compression stage in cooperation with the oppositelower rollers 18 by being controlled so that each of these rollersexerts a higher pressure upon the inner stringer 5 of the upper chain 3than the preceding roller so as to effect a successive compression ofthe layer 21 of fibers, wood chips, or the like until it has the finalthickness of the fiber or chip board which is to be produced. Thesubsequent upper pressure rollers 17 together with the opposite lowerrollers 18, the intermediate inner stringers 5 and 6 of chains 3 and 41and the intermediate parts of belts 7 and 8 form the setting stage ofthe machine, that is, the stage in which the binder in the previouslycompressed fibrous material is set and hardened. These subsequent upperpressure rollers 17 are movable by their hydraulic or pneumatic unitstoward these lower rollers 18 only so far that the slot between theparts of the belts 7 and 8 subsequent to the compression stage will havea uniform thickness and the surfaces of these belt parts will extendparallel to each other up to the outlet end of the machine from whichthe fiber or chip board is delivered.

As may be seen in FIG. 1, the diameters of the pressure rollers 17 and18 are made of such a size that during the travel of the two chains 3and 4 each link plate 19 and 20 of these chains will engage with and beacted upon by at least two laterally adjacent pressure rollers 17 and18, respectively. Each link plate 19 and 20 therefore has a length equalto at least twice the distance between the axes of two adjacent pressurerollers 17 or' 18, respectively. Consequently, each link plate 19 and 20will at all times be acted upon by the pressure of at least two upperpressure rollers 17 and two lower pressure rollers 18, respectively.

For setting the binder in the fiber or chip layer 21 after it has beencompressed to its final thickness, for example, by the pressure rollers17a to 17d, the outer stringers of the two link chains 3 and 4 areadapted to be heated by suitable heating means, for example, by gasburners 22 and 23. In addition, the endless belts 7 and 8 surroundingthe link chains 3 and 4 may be heated, for example, by electric heatingplates 24 and 25.

FIG. 2 illustrates a pair of opposite pressure rollers 17 and 18 of thesetting stage of the pressure subsequent to the pressure rollers 17a to17d of the compres sion stage. These rollers are rotatably mounted inbearings 26, 27 and 28, 29, respectively. For preventing all pressurerollers 17 and 18 from bending between their ends which are mounted inthe bearings 26 to 29, or from tilting out of a horizontal plane, eachupper and lower pressure roller 17 and 18 is supported at the center ofits length by a pair of bracing rollers 30 and 31 or 32 and 33,respectively, as shown in FIGS. 2 and 3 but not visible in H6. 1. Thesebracing rollers are rotatably mounted in bearings 34' and 35 or 36 and37, respectively, which, in turn, are mounted on the piston rods 38 or39 of hydraulic 0r pneumatic units the cylinders of which are mounted onfram e 1 or frame 2, respectively. These units are therefore controlledso that the line of engagement of each pressure roller 17 or 18 with therespective link plate 19 or 211 will at all times be straight and theopposite sides of the slot between the parts of belts 7 and 8 on thelink plates 19 and 20 upon which the respective pressure rollers actwill always be parallel to each other, as seen in the direction of thelength of each pressure roller. Suitable adjustable control means, notshown, should also be provided for the hydraulic or pneumatic unitsacting upon the bracing rollers 30 and 31 or 32 and 33 and upon thebearings 26 and 27 of eachpressure roller 17 or 18 for insuring that thefinished fiber or chip board delivered by the machine will have thedesired uniform thickness.

As shown in FlG. 2, it may be advisable, especially if the machineaccording to the invention forms a final press, to provide equal butexchangable spacing bars 40 between the bearings 26 and 27 of each upperpressure roller 17 and the bearings 28 and 29! of the correspondinglower pressure roller 18 of the entire setting stage of the press whichfollows the compression stage which is formed, for example, by thepressure rollers 17a to 17d and the corresponding lower rollers 13. Asfurther indicated diagrammatically in PEG. 2, some or all of the upperand lower pressure rollers 17 and 18 of the compression and settingstages may be driven by being connected by drive shafts 42 and 43 to acommon gear unit 41. Of course, the individual pressure rollers may alsobe driven by separate drive means which are properly synchronized witheach other.

Although my invention has been illustrated and described with referenceto the preferred embodiment thereof, 1 wish to have it understood thatit is in no way limited to the details of such embodiment but is capableof numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim is: v

1. A press for continuously producing fiber board, chip board or thelike comprising an upper and a lower endless link chain, each of saidchains being movable around and between guide rollers or the likerotatable in one direction about horizontal parallel axes, and each linkchain consisting of a plurality of rigid link plates of a uniform lengtheach of which is pivotably connected at its longitudinal ends to theadjacent link plates, an endless feed belt extending around each chain,said belt being acted upon and adapted to travel with the link plates ofthe inner stringers of said chains facing each other, a plurality ofpressure rollers rotatable about horizontal parallel axes between theinner and outer stringers of each chain, said axis of each pressureroller associated with one chain being disposed within a vertical planeextending through the axis of a pressure roller associated with theother chain, adjustable pressure means acting upon said pressure rollersassociated with said inner stringer at least of one of said chains forpressing the link plates of said stringer and said feed belt thereontoward the other feed belt and the link plates of the inner stringer ofthe other chain, and means for synchronously driving at least some ofsaid pressure rollers acting upon said link plates of said innerstringers of both chains and for thereby synchronously driving saidinner stringers and said belts thereon, each of said link plates havinga length at least equal to twice the distance between the axes of twoadjacent pressure rollers acting upon the same chain.

2. A press as defined in claim 1, further comprising means for heatingat least said chains for. setting and hardening the materials of saidboard after being compressed to its final thickness.

3. A press as defined in claim 1, in which the ends of all of saidpressure rollers are rotatably mounted in bearings, said bearings ofsaid pressure rollers associated with the inner stringer of at least afirst of said chains being adapted to be acted upon and to be moved bysaid pressure means in the direction toward and away from the bearingsof the opposite pressure rollers associated with the inner stringer ofthe second chain,

a plurality of said pressure rollers adjacent to each other near theinlet end of said press which are associated with said inner stringersof said two chains and the endless belt thereon forming a compressionstage for compressing a loose layer of the materials of which said boardis composed substantially to the desired final thickness of said board,and a plurality of said pressure rollers subsequent to those near saidinlet end and asso ciated with said inner stringers of said two chainsand the endless belts thereon forming a heat-setting stage for settingand hardening said board at its final thickness, and means for heatingat least said inner stringers at least within said setting stage.

4. A press as defined in claim 3, further comprising means for alsoheating said endless belt at least within said setting stage.

5. A press as defined in claim 3, further comprising means for bracingat least the central part of the length of all of said pressure rollersat least of said setting stage so as to prevent said rollers frombending.

6. A press as defined in claim 5, in which said bracing means comprise apair of bracing rollers rotatably mounted and engaging upon theperiphery of at least the central part of each of said pressure rollersof both stages at equal distances from a vertical plane extendingthrough the line of engagement of said pressure roller with said innerstringer of the associated chain and also of the engagement of theopposite pressure roller with said inner stringer of the other chain,and adjustable pressure means acting upon said bracing rollers with apressure substantially in conformity with the pressure to which saidbearings of said pressure rollers are subjected.

7. A press for continuously producing boards such as chipboards,fiberboards, and the like; said press comprising:

a first endless chain formed of a plurality of link plates hingedlyconnected to one another at the ends thereof;

a second endless chain formed of a plurality of link plates hingedlyconnected to one another at the ends thereof;

guiding and moving means for guiding and moving said first and secondchains with respective outer surfaces of said chains in facingrelationship and moving in the same direction over a material pressingportion of the respective travel paths of said chains such that boardmaterial for forming said boards can be conveyed by and compressedbetween said chains along said material pressing portion of saidrespective travel paths; and

pressure applying means for pressing said chains toward one anotheralong said material pressing portion of the respective travel paths ofsaid chains such that board material may be forcefully compressedbetween said chains, said pressure applying means including a pluralityof pressure rollers arranged inside of the travel path of at least oneof said chains and forcing means for forcing said pressure rollersagainst the link plates of said at least one chain;

wherein said guiding and moving means includes drive means for rotatablydriving at least one of said pressure rollers such that said at leastone of said pressure rollers applies moving forces to said link platesto move said at least one of said chains along its respective travelpath.

8. A press according to claim 7, further comprising a first flexiblefeed belt enclosing a portion of and movable with said first chain and asecond flexible feed belt enclosing a portion of and movable with saidsecond chain, wherein said first and second belts are interposed betweensaid chains over said material pressing portion of the respective travelpaths thereof to directly engage said board material during pressingoperations.

9. A press according to claim 8, wherein each of said first and secondbelts are endless belts which com pletely surround the respective firstand second chains.

10. A press according to claim 7, wherein said pressure applying meansincludes a plurality of pressure rollers inside each of said chains,wherein said forcing means includes means for forcibly moving thepressure rollers inside of said first chain in a direction transverse tothe direction of travel of said chains, and wherein the pressure rollersin said second chain are maintained in a relatively fixed position forrotation about respective roller axes extending transverse to thedirection of travel of said chains.

ll. A press according to claim l0, wherein the pressure rollers in saidfirst chain are rotatable about re spective axes extending transversetothe direction of travel of said chains, and wherein each of saidpressure rollers in said first chain are constrained to move with theirrespective axes movable in a plane which also contains the axis of arespective one of said pressure rollers in said second chain.

12. A press according to claim 1 1, wherein said drive means includesmeans for synchronously driving respective oppositely-facing pressurerollers in said first and second chains.

13. A press according to claim 12, wherein said drive means includesmeans for driving a plurality of pressure rollers in each of saidchains.

14. A press according to claim 12, wherein said forcing means includesseparate piston and cylinder means for each of said pressure rollers insaid first chain, and wherein control means are provided for controllingsaid piston and cylinder means to sequentially compress the boardmaterial with continuously decreasing distance between said chains alonga first part of said material pressing portion of said respective travelpaths and to maintain a fixed distance between said chains along thepart of said material pressing portion of said respective travel pathswhich follows said first part.

15. A press according to claim 7, wherein said forcing means includesseparate piston and cylinder means for each of said pressure rollers insaid first chain, and wherein control means are provided for controllingsaid piston and cylinder means to sequentially compress the boardmaterial with continuously decreasing distance between said chains alonga first part of said material pressing portion of said respective travelpaths and to maintain a fixed distance between said chains along thepart of said material pressing portion of said respective travel pathswhich follows said first part.

16. A press according to claim 14, wherein said drive means includesmeans for driving a plurality of pressure rollers in each of saidchains.

17. A press according to claim 16, wherein said guiding and moving meansincludes two-spaced reversing guide wheels for each chain, wherein saidmaterial pressing portion of said respective travel paths extendsbetween said reversing guide wheels, and wherein each of said pressurerollers is spaced from said guide wheels. 7 v

18. A press according to claim 7, wherein said guiding and moving meansincludes two-spaced reversing guide wheels for each chain, wherein saidmaterial pressing portion of said respective travel paths extendsbetween said reversing guide wheels, and wherein each of said pressurerollers is spaced from said guide wheels.

19. A press for continuously producing boards such as chipboards,fiberboards, and the like, said press comprising:

a first endless chain formed of a plurality of link plates hingedlyconnected to one another at the ends thereof;

a second endless chain formed of a plurality of link plates hingedlyconnected to one another at the ends thereof;

guiding and moving means for'guiding and moving said first and secondchains with respective outer surfaces of said chains in facingrelationship and moving in the same direction over a material pressingportion of the respective travel paths of said chains such that boardmaterial for forming said boards can be conveyed by and compressedbetween said chains along said material pressing portion of saidrespective travel paths;

and pressure applying means for pressing-said chains toward one anotheralong said material pressing portion of the respective travel paths ofsaid chains such that board material may be forcefully compressedbetween said chains, said pressure applying means including apluralityof pressure rollers arranged inside of the travel path of at least oneof said chains and forcing means for forcing said pressure rollersagainst the link plates of said at least one chain;

wherein said pressure rollers are rotatable about respective axesextending transverse to the direction of travel of said chains, andwherein back-up support means are provided intermediate the ends of atleast some of said rollers, said back-up support means including meansfor applying an adjustable pressure against said rollers separate fromthe forces applied against said rollers by said forcing means.

20. A press according to claim 19, wherein said guiding and moving meansincludes drive means for rotatably driving at least one of said pressurerollers such that said at least one of said pressure rollers appliedmoving forces to said link plates to move said at least one of saidchains along its respective travel path.

21. A press according to claim 19, wherein said pres sure rollers arerotatably supported in bearing means at respective opposite ends of saidpressure rollers, and wherein said forcing means include piston-cylindermeans for moving said bearing means.

22. A press according to claim 21, wherein said backup support meansincludes at least one rotatable member engageable, respectively, withthe surface of each of said at least some of said rollers at a positionintermediate said bearing means.

23. A press according to claim 22, wherein said backup support meansincludes piston-cylinder means separate from the forcing means foradjustably moving each of said at least one rotatable members in adirection transverse to the respective axes of rotation of said rollers.

24. A press according to claim 23, wherein said backup support meansincludes a pair of rotatable members for each of said pressure rollers,the rotatable members of each pair being spaced circumferentially fromone another around the respective pressure roller and being movabletogether by said piston-cylinder means for said back-up support means.

25. A press according to claim 24, wherein oppositely facing pressurerollers inside said first and second chains are provided with a pair ofsaid rotatable members.

26. A press according to claim 23, wherein said rotatable members arerotatable about respective axes extending parallel to the rotationalaxes of said rollers.

27. A press according to claim 23, wherein said guiding and moving meansincludes drive means for rotatably driving at least one of said pressurerollers such that said at least one of said pressure rollers appliesmoving forces to said link plates to move said at least one of saidchains along its respective travel path.

28. A press according to claim 9, further comprising a first flexiblefeed belt enclosing a portion of and movable with said first chain and asecond flexible feed belt enclosing a portion of and movable with saidsecond chain, wherein said first and second belts are inter posedbetween said chains over said material pressing portion of therespective travel paths thereof to directly engage said based materialduring pressing operations.

29. A press according to claim 28, wherein each of said first and secondbelts are endless belts which completely surround the respective firstand second chains.

30. A press according to claim 20, wherein said pressure applying meansincludes a plurality of pressure rollers inside each of said chains,wherein said forcing means includes means for forcibly moving thepressure rollers inside of said first chain in a direction transverse tothe direction of travel of said chains, and wherein the pressure rollersin said second chain are maintained in a relatively fixed position forrotation about respective roller axes extending transverse to thedirection of travel of said chains.

31. A press according to claim 36, wherein the pressure rollers in saidfirst chain are rotatable about respective axes extending transverse tothe direction of travel of said chains, and wherein each of saidpressure.

rollers in said first chain are constrained to move with theirrespective axes movable in a plane which also contains the axis of arespective one of said pressure rollers in said second chain.

32. A press according to claim 31, wherein said drive means includesmeans for synchronously driving respective oppositely-facing pressurerollers in said first and second chains.

33.. A press according to claim 32, wherein said forcing means includesseparate piston and cylinder means for each of said pressure rollers insaid first chain, and wherein control means are provided for controllingsaid piston and cylinder means to sequentially compress the boardmaterial with continuously decreasing distance between said chains alonga first part of said material pressing portion of said respective travelpaths and to maintain a fixed distance between said chains along thepart of said material pressing portion of said respective travel pathswhich follows said first part.

34. A press according to claim 7, wherein the spacing between therotational axes of adjacent pressure rollers in the direction ofmovement of the chains is less than the length of one of said linkplates in said direction of movement of the chains to assure that atleast two pressure rollers are in engagement with a link plate at allpositions along said material pressing portion of the travel paths ofsaid chains except the extreme end positions adjacent respective firstand last pressure rollers in the direction of chain travel.

35. A press according to claim 19, wherein the spaclers in the directionof chain travel.

1. A press for continuously producing fiber board, chip board or thelike comprising an upper and a lower endless link chain, each of saidchains being movable around and between guide rollers or the likerotatable in one direction about horizontal parallel axes, and each linkchain consisting of a plurality of rigid link plates of a uniform lengtheach of which is pivotably connected at its longitudinal ends to theadjacent link plates, an endless feed belt extending around each chain,said belt being acted upon and adapted to travel with the link plates ofthe inner stringers of said chains facing each other, a plurality ofpressure rollers rotatable about horizontal parallel axes between theinner and outer stringers of each chain, said axis of each pressureroller associated with one chain being disposed within a vertical planeextending through the axis of a pressure roller associated with theother chain, adjustable pressure means acting upon said pressure rollersassociated with said inner stringer at least of one of said chains forpressing the link plates of said stringer and said feed belt thereontoward the other feed belt and the link plates of the inner stringer ofthe other chain, and means for synchronously driving at least some ofsaid pressure rollers acting upon said link plates of said innerstringers of both chains and for thereby synchronously driving saidinner stringers and said belts thereon, each of said link plates havinga length at least equal to twice the distance between the axes of twoadjacent pressure rollers acting upon the same chain.
 2. A press asdefined in claim 1, further comprising means for heating at least saidchains for setting and hardening the materials of said board after beingcompressed to its final thickness.
 3. A press as defined in claim 1, inwhich the ends of all of said pressure rollers are rotatably mounted inbearings, said bearings of said pressure rollers associated with theinner stringer of at least a first of said chains being adapted to beacted upon and to be moved by said pressure means in the directiontoward and away from the bearings of the opposite pressure rollersassociated with the inner stringer of the second chain, a plurality ofsaid pressure rollers adjacent to each other near the inlet end of saidpress which are associated with said inner stringers of said two chainsand the endless belt thereon forming a compression stage for compressinga loose layer of the materials of which said board is composedsubstantially to the desired final thickness of said board, and aplurality of said pressure rollers subsequent to those near said inletend and associated with said inner stringers of said two chains and theendless belts thereon forming a heat-setting stage for setting andhardening said board at its final thickness, and means for heating atleast said inner stringers at least within said setting stage.
 4. Apress as defined in claim 3, further comprising means for also heatingsaid endless belt at least within said setting stage.
 5. A press asdefined in claim 3, further comprising means for bracing at least thecentral part of the length of all of said pressure rollers at least ofsaid setting stage so as to prevent said rollers from beNding.
 6. Apress as defined in claim 5, in which said bracing means comprise a pairof bracing rollers rotatably mounted and engaging upon the periphery ofat least the central part of each of said pressure rollers of bothstages at equal distances from a vertical plane extending through theline of engagement of said pressure roller with said inner stringer ofthe associated chain and also of the engagement of the opposite pressureroller with said inner stringer of the other chain, and adjustablepressure means acting upon said bracing rollers with a pressuresubstantially in conformity with the pressure to which said bearings ofsaid pressure rollers are subjected.
 7. A press for continuouslyproducing boards such as chipboards, fiberboards, and the like; saidpress comprising: a first endless chain formed of a plurality of linkplates hingedly connected to one another at the ends thereof; a secondendless chain formed of a plurality of link plates hingedly connected toone another at the ends thereof; guiding and moving means for guidingand moving said first and second chains with respective outer surfacesof said chains in facing relationship and moving in the same directionover a material pressing portion of the respective travel paths of saidchains such that board material for forming said boards can be conveyedby and compressed between said chains along said material pressingportion of said respective travel paths; and pressure applying means forpressing said chains toward one another along said material pressingportion of the respective travel paths of said chains such that boardmaterial may be forcefully compressed between said chains, said pressureapplying means including a plurality of pressure rollers arranged insideof the travel path of at least one of said chains and forcing means forforcing said pressure rollers against the link plates of said at leastone chain; wherein said guiding and moving means includes drive meansfor rotatably driving at least one of said pressure rollers such thatsaid at least one of said pressure rollers applies moving forces to saidlink plates to move said at least one of said chains along itsrespective travel path.
 8. A press according to claim 7, furthercomprising a first flexible feed belt enclosing a portion of and movablewith said first chain and a second flexible feed belt enclosing aportion of and movable with said second chain, wherein said first andsecond belts are interposed between said chains over said materialpressing portion of the respective travel paths thereof to directlyengage said board material during pressing operations.
 9. A pressaccording to claim 8, wherein each of said first and second belts areendless belts which completely surround the respective first and secondchains.
 10. A press according to claim 7, wherein said pressure applyingmeans includes a plurality of pressure rollers inside each of saidchains, wherein said forcing means includes means for forcibly movingthe pressure rollers inside of said first chain in a directiontransverse to the direction of travel of said chains, and wherein thepressure rollers in said second chain are maintained in a relativelyfixed position for rotation about respective roller axes extendingtransverse to the direction of travel of said chains.
 11. A pressaccording to claim 10, wherein the pressure rollers in said first chainare rotatable about respective axes extending transverse to thedirection of travel of said chains, and wherein each of said pressurerollers in said first chain are constrained to move with theirrespective axes movable in a plane which also contains the axis of arespective one of said pressure rollers in said second chain.
 12. Apress according to claim 11, wherein said drive means includes means forsynchronously driving respective oppositely-facing pressure rollers insaid first and second chains.
 13. A press according to claim 12, whereinsaid drive means includes Means for driving a plurality of pressurerollers in each of said chains.
 14. A press according to claim 12,wherein said forcing means includes separate piston and cylinder meansfor each of said pressure rollers in said first chain, and whereincontrol means are provided for controlling said piston and cylindermeans to sequentially compress the board material with continuouslydecreasing distance between said chains along a first part of saidmaterial pressing portion of said respective travel paths and tomaintain a fixed distance between said chains along the part of saidmaterial pressing portion of said respective travel paths which followssaid first part.
 15. A press according to claim 7, wherein said forcingmeans includes separate piston and cylinder means for each of saidpressure rollers in said first chain, and wherein control means areprovided for controlling said piston and cylinder means to sequentiallycompress the board material with continuously decreasing distancebetween said chains along a first part of said material pressing portionof said respective travel paths and to maintain a fixed distance betweensaid chains along the part of said material pressing portion of saidrespective travel paths which follows said first part.
 16. A pressaccording to claim 14, wherein said drive means includes means fordriving a plurality of pressure rollers in each of said chains.
 17. Apress according to claim 16, wherein said guiding and moving meansincludes two-spaced reversing guide wheels for each chain, wherein saidmaterial pressing portion of said respective travel paths extendsbetween said reversing guide wheels, and wherein each of said pressurerollers is spaced from said guide wheels.
 18. A press according to claim7, wherein said guiding and moving means includes two-spaced reversingguide wheels for each chain, wherein said material pressing portion ofsaid respective travel paths extends between said reversing guidewheels, and wherein each of said pressure rollers is spaced from saidguide wheels.
 19. A press for continuously producing boards such aschipboards, fiberboards, and the like, said press comprising: a firstendless chain formed of a plurality of link plates hingedly connected toone another at the ends thereof; a second endless chain formed of aplurality of link plates hingedly connected to one another at the endsthereof; guiding and moving means for guiding and moving said first andsecond chains with respective outer surfaces of said chains in facingrelationship and moving in the same direction over a material pressingportion of the respective travel paths of said chains such that boardmaterial for forming said boards can be conveyed by and compressedbetween said chains along said material pressing portion of saidrespective travel paths; and pressure applying means for pressing saidchains toward one another along said material pressing portion of therespective travel paths of said chains such that board material may beforcefully compressed between said chains, said pressure applying meansincluding a plurality of pressure rollers arranged inside of the travelpath of at least one of said chains and forcing means for forcing saidpressure rollers against the link plates of said at least one chain;wherein said pressure rollers are rotatable about respective axesextending transverse to the direction of travel of said chains, andwherein back-up support means are provided intermediate the ends of atleast some of said rollers, said back-up support means including meansfor applying an adjustable pressure against said rollers separate fromthe forces applied against said rollers by said forcing means.
 20. Apress according to claim 19, wherein said guiding and moving meansincludes drive means for rotatably driving at least one of said pressurerollers such that said at least one of said pressure rollers appliedmoving forces to said link plates to move said at least one of saidchains alOng its respective travel path.
 21. A press according to claim19, wherein said pressure rollers are rotatably supported in bearingmeans at respective opposite ends of said pressure rollers, and whereinsaid forcing means include piston-cylinder means for moving said bearingmeans.
 22. A press according to claim 21, wherein said back-up supportmeans includes at least one rotatable member engageable, respectively,with the surface of each of said at least some of said rollers at aposition intermediate said bearing means.
 23. A press according to claim22, wherein said back-up support means includes piston-cylinder meansseparate from the forcing means for adjustably moving each of said atleast one rotatable members in a direction transverse to the respectiveaxes of rotation of said rollers.
 24. A press according to claim 23,wherein said back-up support means includes a pair of rotatable membersfor each of said pressure rollers, the rotatable members of each pairbeing spaced circumferentially from one another around the respectivepressure roller and being movable together by said piston-cylinder meansfor said back-up support means.
 25. A press according to claim 24,wherein oppositely facing pressure rollers inside said first and secondchains are provided with a pair of said rotatable members.
 26. A pressaccording to claim 23, wherein said rotatable members are rotatableabout respective axes extending parallel to the rotational axes of saidrollers.
 27. A press according to claim 23, wherein said guiding andmoving means includes drive means for rotatably driving at least one ofsaid pressure rollers such that said at least one of said pressurerollers applies moving forces to said link plates to move said at leastone of said chains along its respective travel path.
 28. A pressaccording to claim 9, further comprising a first flexible feed beltenclosing a portion of and movable with said first chain and a secondflexible feed belt enclosing a portion of and movable with said secondchain, wherein said first and second belts are interposed between saidchains over said material pressing portion of the respective travelpaths thereof to directly engage said based material during pressingoperations.
 29. A press according to claim 28, wherein each of saidfirst and second belts are endless belts which completely surround therespective first and second chains.
 30. A press according to claim 20,wherein said pressure applying means includes a plurality of pressurerollers inside each of said chains, wherein said forcing means includesmeans for forcibly moving the pressure rollers inside of said firstchain in a direction transverse to the direction of travel of saidchains, and wherein the pressure rollers in said second chain aremaintained in a relatively fixed position for rotation about respectiveroller axes extending transverse to the direction of travel of saidchains.
 31. A press according to claim 30, wherein the pressure rollersin said first chain are rotatable about respective axes extendingtransverse to the direction of travel of said chains, and wherein eachof said pressure rollers in said first chain are constrained to movewith their respective axes movable in a plane which also contains theaxis of a respective one of said pressure rollers in said second chain.32. A press according to claim 31, wherein said drive means includesmeans for synchronously driving respective oppositely-facing pressurerollers in said first and second chains.
 33. A press according to claim32, wherein said forcing means includes separate piston and cylindermeans for each of said pressure rollers in said first chain, and whereincontrol means are provided for controlling said piston and cylindermeans to sequentially compress the board material with continuouslydecreasing distance between said chains along a first part of saidmaterial pressing portion of said respective travel paths and tomaintain a fixed distance between said chains along the part of saidmaterial pressing portion of said respective travel paths which followssaid first part.
 34. A press according to claim 7, wherein the spacingbetween the rotational axes of adjacent pressure rollers in thedirection of movement of the chains is less than the length of one ofsaid link plates in said direction of movement of the chains to assurethat at least two pressure rollers are in engagement with a link plateat all positions along said material pressing portion of the travelpaths of said chains except the extreme end positions adjacentrespective first and last pressure rollers in the direction of chaintravel.
 35. A press according to claim 19, wherein the spacing betweenthe rotational axes of adjacent pressure rollers in the direction ofmovement of the chains is less than the length of one of said linkplates in said direction of movement of the chains to assure that atleast two pressure rollers are in engagement with a link plate at allpositions along said material pressing portion of the travel paths ofsaid chains except the extreme end positions adjacent respective firstand last pressure rollers in the direction of chain travel.